I'm not sure of the question here, as it honestly appears that you've already made up your mind on this matter:

- You've listed all the benefits of living in the UK and Scotland and virtually none of the negatives
- You've listed all of the negatives of living in the U.S. and virtually none of the benefits (except that you're in the same country, but not the same state as your son)

You've tried this once already and got so depressed you moved back over to the U.S., but it sounds like it's just been too difficult and frustrating for you to stay.

So I'd say you have your answer -- you've tried, you seem to have given up on trying to live here and you want to move back over to the UK where you see the grass is greener. As long as you feel you can handle/cope with the depression associated with not being "near" your son, it sounds as if your mind is already made up.

DocJohn